1. Field of the Invention
The invention relates to a projectile fuze in which the time of flight (T) can be programmed, having a timer/counter which counts up to the programmed time of flight (T)—minus a defined time value (Δt)—and then charges an electrical firing circuit. A mechanical safety and arming unit switches the firing circuit, which has an electrical detonator, a firing needle, a piercing detonator and a booster charge, to an armed position after a specific time interval. The projectile fuze, for example, may be used as a mortar fuze.
2. Discussion of the Prior Art
Projectile fuzes are known which possess a so-called overflight safety. Such an overflight safety has been introduced in the form of an electrical solution, for example, for a fuze with the type designation ANNZ DM 74. This known overflight safety is used to make the projectile fuze resistant to jamming attempts and/or to spoofing attempts by an enemy, and against rarely occurring influences, both external and internal, over a relatively long section of the projectile trajectory. The so-called trajectory decomposition rate for known projectile fuzes such as these is less than 10−6. This means that a projectile fitted with a projectile fuze such as this can now even be used over one's own troops. This applies, for example, to exercises using projectiles which are equipped with projectile fuzes such as these.
Electrical overflight safety such as described is achieved by programming, that is to say feeding the time of flight of the projectile into the fuze electronics by means of an external programmer. Once the projectile has been fired, a timer/counter is started, which counts up to the programmed time of flight—minus a defined time value—and then charges an electrical firing circuit for the fuze electronics. The time required to charge the firing circuit in this manner is in the region of milliseconds, so that the projectile fuze is ready to fire in good time at the predetermined target.
However, in the case of the known projectile fazes of the type mentioned above, the safety and arming unit is designed such that, even after a time interval which is very short in comparison to the overall trajectory, the mechanical interruption in the firing chain is removed, that is to say the so-called safe separation distance is comparatively short.